1. Field
Embodiments of the present invention relate to a mounting structure for an in-wheel motor system which allows the in-wheel motor system to be stably installed in a wheel of a vehicle and may increase efficiency of mounting and detaching of the in-wheel motor system.
2. Description of the Related Art
In general, an in-wheel motor, which is a technology applied to an electric motor using electricity as its power source, allows power to be directly transmitted from the motor disposed inside a rim of a wheel to the wheel, unlike transmission of power to the wheel through an engine, a transmission and a drive shaft to rotate the wheel in a gasoline-powered or diesel-powered vehicle.
Such an in-wheel motor may eliminate the need for driving and power transmitting devices such as an engine, transmission and differential gears, and thereby reduce the weight of the vehicle, provide independent control of the wheel, improve drive performance, and lower energy loss in power transmission.
FIG. 1 is a perspective view schematically illustrating installation of a conventional in-wheel motor system in a wheel, and FIG. 2 is a cross-sectional view illustrating the assembly of the in-wheel motor system of FIG. 1.
With reference to FIG. 1, when the in-wheel motor system is mounted to the wheel 10, it is moved from the inside of the vehicle toward the outside of the vehicle. The in-wheel motor system includes an axle 20 installed at the center of the wheel 10 to rotate along with the wheel 10, a reducer 30 to reduce the rotational force of the in-wheel motor 40 and transmit the reduced force to the axle 20, an in-wheel motor 40 connected to the reducer 30, and a disc brake 60 to generate braking force by applying pressure to a disc 50 arranged between the wheel 10 and the axle 20.
In such an in-wheel motor system, the reducer 30 needs to be provided to increase torque of the in-wheel motor 40, and a brake system performing braking, i.e., the disc 50 and the disc brake 60 need to be installed in the wheel 10, and thereby fastening the in-wheel motor system to the wheel 10 may result in inefficient use of space and poor drivability of the vehicle due to increase in unsprung mass.
Further, when the in-wheel motor system is mounted to the wheel 10, the disc 50, disc brake 60 and reducer 30 are positioned in the wheel, but due to limitation of the space in the wheel 30, the in-wheel motor 40 may protrude to the outside of the wheel 10, that is, toward the inside of the vehicle, and thus be damaged by shock from an external object.
Further, mounting the in-wheel motor system to the vehicle through a bracket (not shown), which usually has two bolt fastening holes, may prevent stable installation of the in-wheel motor system at the vehicle through a motor housing 41 of the in-wheel motor 40, resulting in uncertain effectiveness of support of the fastened in-wheel motor system when vibration and shock are transferred to the system from the road surface.
Korean Patent No. 10-0875004 discloses a structure of mounting an in-wheel motor system to a vehicle. According to the disclosure of the document, the in-wheel motor mounting structure is provided with a bolt fastening hole at a bracket of a stator of the in-wheel motor to allow a bolt to penetrate the hole, and the knuckle (bracket) to be installed at the vehicle is provided with two through holes which are penetrated by bolts, such that the bolts are fastened to the bolt fastening holes in the bracket of the stator through the through holes in the knuckle. That is, as described above, the effectiveness of the strength to support fastening of the in-wheel motor to the vehicle may be uncertain as vibration and shock are transferred from the road surface, and there may be a danger of damage to the system by external shock.